Water treatment device



Patented hilary lid, ldt

` amica awareness site aus@ r, ieee, sensi ne. tiener,

The invention relates to improvements in water treatment devices oriluid filtering ystems or plants, and is more particularly irected tothe construction of a rapid sand y filter which serves as an underdrainsystem liti `for the lilter and distribution system tor the gter orother mediumv used in washing the @ne of the objects of the presentinvention is to provide an improved construction of a filter bottom tora iluid filtration plant or system.

3i further object of the invention is to rovide an improved constructionot a iilter ottone. which will serve as an ediciont distributing mediumfor the wash Water when the filter is being cleansed.

A. further object in the invention is to provide an improvedconstruction of a filter bottom which will form a substantial anddependable support for the overlying,` sand bed.

A further object ci the invention is to rovide a construction of a ilterbottom w ich` will reduce the cost of construction as well as the costot maintenance.

These and other objects are accomplished by providing a construction inthe arrangement of the various parts in the manner heretofore described,and particularly pointed out in the appended claims.

Referring to the drawings,

Figure l is a fragmentary top plan view ol a portion of the filteringplant showing my improved filter bottom embodied therein, with certainportions of the filtering medium broken away i'or the purpose ofclearness;

Figure 2 is a cross-sectional view taken on the line 2-2 of Figure l;and

lli re 3 is a cross-sectional view taken on the line 3-3 of Figure 2.

lln iltering plants or systems that have been used heretofore, 'of theconstruction in which the layers of gravel are carefully grraded so thatthe overlying" sand is kept Jfrom working its way down through theconventional gravel bed into the underdrains, particular attention ispaid tothe top layer which is relied upon principally to prevent thesand from getting a start on its downward course.

lin these tr pes of' filter, this top layer is moet easil isturbed byinequality in washing and y the sudden release ot air entrained in thefilter bed and underdrains, and in the attempt to provide a dependablebarrier against t e breaking through of the sand the top layer of gravelhas in various instances been cemented together to 'form a porous layerbetween the main gravel bed and the overlying sand. Heretcore theoutstanding disadvantage ot this type of filter has been its structuralweakness in forming a crust on the top of the graded gravel bed. Withthis construction there is always a lift tendono for failure to occur inthe bending m or brea ing ot the porous layer by the action oil2 theupward water thrust. This is because the porous layer in this ty e oflter is resting, on the loose gravel an only supported in position atthe outer edges to the lter structure, leaving the center unsupported.

have overcome these disadvantages by providing a construction as shownin the drawings, which involves a novel constrnc tion oia a llter bottomwhich combines the function ot the underdrain system for the filter whenduid is being filtered, and a distribution system for the Wash water orother cleansing'element which is introduced into the lter structure in adirection reverse from that in which the system is normally used for theiiltration of fluid.

For the purpose of illustration, l have shown and described by inventionin connection with the water filtration plant or system, but it will ofcourse be understood that the same is capable of use in connection withfluids generally, such as zfrases, air, and liquids, and l therefore donot wish to limit myself unnecessarily. lt will als/o be noted thatwhile the invention is specifically adapted for a conventional, rapidsand filter, the same may be used in connection with water softening'devices, such for instance, as a combined underdrain and dis-v tribution(diffusing) s stein, and still be within contemplation o my invention.

When my improved porous slab construction of combined underdrain anddistribution system is used in connection with water softening devicesas referred to in the preceding paragraph, the porous slab should beoverlain by zeolite sand (the water soft- 5 ening material) instead ofquartz sand (used for filtration). Aside from this, the structure isidentical, that is, the structure of the porous slab for use as afiltration or water softening device. v

In the embodiment of the invention as illustrated in the drawing, theessential component parts of one form of the invention comprise astructural filter box 10, only a fragmentary portion of which is shownin the drawing, and a system of wash water laterals or pipes 11, thenumber of which depends upon the size of the filtration plant. Theselaterals are arranged and spaced apart in parallel relation. Extendinglongitudinally of and underneath the laterals or pipes 11 are waterwaysor channels 12.

Cast monolithically between and over the underdrains or pipes 11 andbonded or secured directly to the structural floor 13 of the filterstructure is a porous slab. 14. This porous slab 14 is preferably madeof cemented gravel on account of the universal availability of thematerials entering into the composition, and because of the cheapness ofcost, although it will of course be understood that it is possible tomake the porous slab of a cemented gravel mixture of other cementcontent or composition of different sizes of gravel, as well as slabs ofvarious thicknesses. I have determined that for the economic design ofthe porous slab, which will insure the uniform distribution of the washwater over the surface of the slab, a thickness of about 8", and acement to gravel ratio by volume of 1 to 9 is satisfactory, the gravelitself having an effective size of 2.1 millimeters and a uniformitycoefficient of 1.36. This slab 14, when properly prepared, issufliciently porous to permit the fluids being filtered, or the fiuidsfor washing the filter sand, to pass therethrough, but at the same timewill prevent the passage of the sand grains of the overlying filter sandbed.

The wash water laterals 11 are preferably made of vitrified clay sewerpipe, because in addition to the cheapness, this pipe may be readilyembedded in the porous slab 14 and will constitute an installation thatwill never corrode or Wear out, regardless of the type of water or otherfluid that may be filtered. The laterals or-pipes 11 are preferably madeup of sections 15, which are provided with bell joints as shown in 16,which afford a suitable clearance above the floor 13 of the filterstructure. At these bell joints cemented` baffles or cut-offs 19 arepreferably made, to serve as anchorages for the alignment of the pipelaterals 11 and to break at 65 each bell joint the continuity of thechannels 12 formed in the lower side of the orous slab 14. Saidanchorages and cut-o s are, however, not necessarily a part of theconstruction. While I prefer to use perforated vitrified clay sewer pipein my improved filter bottom, it will be understood that any suitablekind of pipe may be used to accomplish the same result.

In order to overcomev a practical construction difficulty in forminglongitudinally extending waterways beneath each of the'laterals or pipes11 in my improved filter bottom construction, I provide a solublesubstance, such as rock salt, to form a core, having the confi urationof the waterways or channels 12. i'Vhen the cement mixture with thegravel becomes sufiiciently hardened, the water passing through thebottom dissolves thel rock salt, leaving the waterways free for thepassage of the water. Between the cemented cut-offs, as shown at 19, atthe bellshaped joints of the sections 15 of the laterals or pipes 11, Ihave provided a plurality of spaced apart apertures or perforations 20.One end of the laterals 1l extends through the wall 21 of the filterstructure l0 and connects with the main wash water manifold or channel22, while the other end of the laterals terminate within the oppositewall 23, as shown at 24.

Mounted on my improved filter bottom or cemented porous slab 14 is arelatively thick layer of filter sand 225. I sometimes find it desirable-to position between the layer of sand 25 and the porous slab 14 a loosegravel of substantially pea size.

In the operation of my improved filter bottom construction when the sameis used as a filter system, the fiuid being filtered is discharged intothe filter structure above the 105 surface of the filtering sand 25,through which it passes down through the porous slab 14 into theunderdrains or laterals by way of the perforations 20 between thecutofls 19. Each lateral in turn discharges its 110 quota of filteredfluid into the manifold or channel 22.

When the filter bottom is used as a distribution system; that is, whenit becomes necessary to remove the impurities that have 115 collected inthe sand bed, the sand is cleansed in situ by closing the influent orwater supply pipe, and the previously filtered water is forced throughthe underdrain laterals in a direction reverse from that in which thesys- 120 tem is normally used as a filter. The wash Water which isforced up through the porous slab throws the sand grains intosuspension, and the churning and swirling motion of the water loosensall the impurities and organic 125 matters, which are skimmed ofi1 bywash water gutters (not shown), which are normally positioned above thesand layer 25, leaving the sand behind. When the Wash water is shut offthe sand bed settles down 13o into place over the filter bottom orporous slab, in which position the filter system is ready for thcAfurther filtration of iuids.

In addition to the use of low-cost materials in construction, theinstallation of my lilter bottom as a whole places the work ofconstruction in the hands of the same men who do the structural concretework of the lilter unit itself. and permits the employment of the sameclass of materials and equipment, thus making the labor costs forinstallation of this filter bottom substantially less than those ofother existing accepted types of ilters.

While in the above specification I have described one embodiment whichmy invention may assume in practice, it will of course be understoodthat the same is capable of moditication and that modification-may beemployed without departing from the spirit and scope of the invention asexpressed in the fol'- lowing claims:

What I claim as my invention and desire to secure by Letters Patent is:

1. A filter bottom for a water treatment device comprising a porousfiltration medium made of cemented materials, said medium having aplurality of longitudinally extending conduits, said conduits having aplurality of spaced apart apertures therein, there bein a channellocated beneath each conduit an communicating with its respectiveconduit through said apertures.

2. A filter bottom for a water treatment device comprising a porousfiltration medium having a plurality of longitudinally extending spacedapart conduits, said conduits having a plurality of spaced apartapertures on one side thereof, said medium hav- May, 1936.

HARRY NEVILLE JENKS.

ing a plurality of channels located beneath said conduits and spacedapart baiies located in said channels for breaking the continuity ofsaid channels.

3. The combination with a Huid treatmentsA device of a box-like cementstructure having a bottom, a porous slab mounted in and secured to thebottom of said structure, a plurality of longitudinally extendinglaterals secured in said slab, saidslab having passage- Ways extendingbeneath said laterals, there being a plurality of apertures in saidlaterals forming communication between said passageways and saidlaterals and a manifold in communication with said laterals, whereby thecleansing uid passing through said manifold into said laterals isequally distributed throughout said slab. i

4. The combination with a fluid treatment device of a box-like cementstructure having a bottom, a porous slab mounted in and secured to thcbottom of said structure, aplui rality oit-longitudinally extendinglaterals secured in said slab, said slab having passageways extendingbeneath said laterals, there being a plurality of apertures in saidlater-

